The modern home sewing machine is designed to be used with consumer thread spools having an outer diameter from one-half inch up to one and one-half inches with an inner aperture having a diameter of about 5 millimeters. The length of the consumer spool varies from about one-half inches to two inches. Thus, the consumer thread spool cannot contain a large quantity of thread. The limited quantity of thread causes few problems in average sewing; however, when one needs to run a long seam, such as in a quilt, the limited quantity of thread will cause problems.
The industrial spool, naturally, contains a larger quantity of thread; however, the industrial spool is larger and will not fit over the standard thread spool spindle found on a consumer sewing machine. In fact, the industrial spool takes on the shape of a truncated cone which is open at both ends: the industrial spool is known as the Cone Thread Spool. Naturally the top diameter is smaller than the bottom diameter with the top diameter within the range of about 1.8 cm to about 2.5 cm and the corresponding bottom diameter in the range of about 2.0 cm to about 4.0 cm. The actual sizes depend on the quantity and type of thread found on the cone spool. Furthermore, certain specialty threads are available only on industrial spools. It is, therefore, an advantage for the consumer to be able to use the smaller sized industrial spools of thread which have now found their way into the consumer market place.